1. Field of the Invention
The present invention relates to a communication apparatus which can automatically select image communication in the facsimile mode or voice communication in the telephone mode in response to a communication apparatus on the distant side.
2. Description of the Prior Art
As a conventional apparatus of this type, there is known a facsimile apparatus having the automatic reception mode in which an image is automatically transmitted and received in response to a ringing tone signal from a facsimile apparatus on the calling side.
Generally, a facsimile apparatus having the automatic transmitting/receiving function is also provided with the manual reception mode in which the outgoing call or incoming call is performed using an attached telephone set and thereafter the line is switched to the facsimile apparatus and the image communication is executed. In many cases, this automatic-manual switching is performed by a change-over switch provided on an operating panel or the like.
Ordinarily, when the facsimile apparatus is set into the manual mode, a telephone set installed in the facsimile apparatus can be used similarly to an ordinary telephone, and even a call from a public telephone or the like can be received. However, in the case of receiving an original, the operator has to mediate between the transmission and reception sides. Namely, after picking up the handset, the operator has to switch the line to the side of the facsimile apparatus by operating a reception button or a switch.
On the other hand, in the case of the auto reception mode, an image transmitted from the facsimile apparatus can be automatically received. However, in such a case, the ordinary communication function of the telephone set connected to the facsimile apparatus will have been lost, causing the drawback that it is impossible to receive a communication by an outgoing call from a public telephone or the like.
FIG. 1 shows the operation of the facsimile apparatus which has been set into the auto reception mode in the case where it has been called from an ordinary telephone set. This diagram shows the operation of the facsimile apparatus of the G type (group 2) which meets CCITT (International Telegraph and Telephone Consultative Committee) Recommendation T3.
As shown in the diagram, for an outgoing call from an ordinary telephone set, the apparatus which has been set into the auto reception mode first transmits a CED signal 1. This CED signal 1 is a called station identifying signal representing that the called station is the non-voice communication terminal. Subsequently, the facsimile apparatus transmits a GI2 signal 2. This GI2 signal 2 is a group 2 identification signal indicating that the apparatus can perform the communication on the basis of the G2 equipment recommendation method and at least one sheet of original can be received.
Thereafter, the facsimile apparatus waits for a GC2 signal as an identifying signal on the transmitting side corresponding to the GI2 signal 2. However, in the case of an outgoing call from an ordinary telephone set, the GC2 signal obviously will not be transmitted. Therefore, the facsimile apparatus on the receiving side repeats the retransmission of the GI2 signal 2 every three seconds during a predetermined initial identification time interval (ordinarily, for 35 seconds from the first GI2 signal 2, namely, this interval corresponds to about seven transmissions of the GI2 signal 2). If the GC2 signal cannot be received in spite of this repetitive transmission, the facsimile apparatus will have disconnected the line as an error end.
The conventional auto reception is as described above. For instance, the user who has only one telephone line contracted uses the telephone set as an ordinary telephone set as well, so that it is undesirable that the apparatus is always set into the auto reception mode. Consequently, the auto reception mode is a function useless to such a user. In addition, even for such a user, the apparatus is usually set into the auto reception mode at night in the case of communication with foreign countries. If the user forgets to switch the apparatus from the manual mode to the auto mode, the apparatus will not have functioned as the facsimile apparatus in the place where nobody is present at night. Therefore, in a conventional facsimile apparatus, even if both the manual and auto modes are provided, its proper use is troublesome and this results in the user often installing another telephone only for use in the facsimile apparatus. That would make the burden too heavy for the user.
In consideration of the above point, technology has been provided whereby means for identifying a voice on the calling side is provided and the switching of the line is controlled by the voice from the calling side. However, since such an apparatus uses a voice recognizing apparatus, the whole apparatus becomes complicated and this results in an increase in cost and causes the burden for the operator on the calling side to be increased.
The above-mentioned drawback is a common problem for communication apparatuses which perform predetermined communications on the basis of a predetermined protocol by use of telephone lines.